The Car Feature You Don't Want To Use If Your Windshield Is Foggy

Driving a car (or other motor vehicle) is often equal parts convenient and necessary, but it also comes with a number of inherent risks — not the least of which is a foggy windshield. While the circumstances that lead to your car's glass fogging up can vary, it's never a good idea to be on the move when it's difficult to see what's going on in front of or around you.

Fortunately there are a number of ways to deal with windshield fog, with some high-tech solutions still being workshopped. The thing is, with as risky as driving with a fogged-up windshield can be, you'll want to be careful when attempting to clear it up. Some suggested solutions may actually make the situation worse.

So whether you're on the road or (ideally) have just gotten in your car and noticed the fogginess before heading out, here's what you should avoid doing to try and clear up your glass.

One of the more common suggestions when it comes to defogging a windshield is a simple one: Turn on the Recirculate feature for your car's fan system. The reasoning behind this particular option is that it's supposed to keep the interior air circulating and reduce moisture buildup on your windshield (since there are fans positioned just below it, on the dashboard). However, in colder temperatures it can have the opposite effect.

The biggest factor is less the temperature itself and more the amount of moisture in the air — both inside and outside of your car. If the air inside your car isn't dry enough, recirculating it will just keep that moisture trapped and lead to a buildup of condensation. This, of course, will lead to fog. But chilly winter air is usually dry, so by keeping Recirculate turned off the fan system will pull in the less watery air from outside and keep all that moisture from building up on the glass.

You do have plenty of other ways to combat fog on your windshield, though, and most of them can still be implemented without having to leave your car. Granted, hitting your windows with anti-fog spray is still worth thinking about as these sprays do tend to reduce fog buildup on their own, but if you don't have any or are still encountering windshield fog:

1. Before you start driving, or after you've parked in a safe area, take a moment to clean (and dry, if necessary) your windows. Dirt and other road grime can and will sometimes cause unwanted moisture to build up.
2. Turn on the Defroster. Most cars have one for both the rear window (as its own button) and as an option for the fan system — just look for an icon of what looks like a window with a few wavy up arrows below it.
3. Alter the temperature. You can use the AC or the heater to temporarily try and match the outside temperature. Yes this means probably turning the heat on during a hot day, or using the AC on a freezing one, but a drastic difference in temperature between the inside and outside of your car can lead to fogging.

Above all else, if your windshield is fogging up and you aren't able to clear it up immediately, quickly (but mindfully) find a safe place to pull over and park until you can see well enough to move on.